An Italian woman who fled a jail sentence for swiping her dying mother’s $15 million fortune is now holed up in a Trump Tower condo surrounded by heaps of stolen diamonds, antiques and artwork, according to legal papers in a nasty, trans-Atlantic estate battle.

High-rolling fugitive Susetta Mion carted a ton of her mother Renata Forti’s luxury goods across the ocean in August 2007 after she had been sentenced by an Italian judge for thievery, according to filings in Manhattan Surrogate’s Court.

Now Mion’s niece, Boston-based immigration attorney Micol Mion Gordon, 34, is fighting her in US and Italian courts, alleging “surreptitious and unlawful looting” of the estate.

“She ruthlessly misappropriated for her own use and enjoyment her mother’s substantial assets, thereby leaving Renata Forti — a formerly wealthy woman — destitute in her final days,” the legal papers claim.

In January, Surrogate’s Justice Nora Anderson granted Gordon temporary control over the estate, but in a follow-up ruling this month Anderson noted Mion has been refusing to comply with court orders for information about her inheritance.

Before Forti, heir to a textile fortune, died in Milan at age 85 in 2008, Mion allegedly raided her mother’s safes and bank accounts.

In a letter Forti wrote shortly before her death, dated “Christmas 2006,” she railed against Mion.

“Return all my fur coats which you sneaked out of my closet while I was out. Put back all my jewels in my safe, which you emptied out. Affix back on my walls my paintings which you have taken down,” she ordered.

“You have threatened to leave me alone without means to sustain myself.”

Gordon charges that Mion bought her $2.3 million one-bedroom on Fifth Avenue with her ill-gotten gains and filled it with her spoils, including Hermès armchairs, a Yamaha baby grand piano, a 17th-century oil canvas and $150,000 pear-shaped diamond earrings.

She also plunked down $3.2million for two more Trump pads as investments, records show.

The Boston attorney sent spies to one of the units, posing as buyers of the apartment, to confirm the goods belonged to her grandmother.

The investigators took pictures and used a hidden camera, according to court papers, which were reviewed by Forti’s granddaughter Cecilia Mion.

The granddaughter recalled visits to her grandmother’s Milan apartment in an August 2012 sworn statement.

“Renata and I ate lunch on a round table with powder pink chairs in her dining room,” she says in the affidavit. “I recognize this same table and chairs in the attached photographs that depict Unit 40H of The Trump Tower in New York City.”

In opposing papers, Mion insists the money is hers and her niece forged the accusatory letter.

She said the current conflict stems from Italian lawsuits over a bitter settlement of her late father’s estate.